Even if you didn't have mnemonics, you could use tab, arrow keys and alt if needed, to navigate, and space to "click" buttons and such.

So even if the developer forgot to configure mnemonics, which was as easy as prefixing a letter with ampersand, you could navigate by keyboard. Sometimes tedious but beats not being able.

> Not guaranteed but easy, because Windows has mnemonics, where you can associate arbitrarily nested menus with actions, and each menu can have its own mnemonic key, so that you press ALT, then, say, "k", then, maybe "m" and so on, following along with the menus as they drop down.

> I'd even say friendlier than MacOS (heresy!!)

Honestly, I disagree. If you've used macOS for a length of time, you might be aware of the universal menu search system using (cmd+? i.e. cmd+shift+/). Hit that, type the menu item name, and simply hit return to activate it. Doesn't get simpler than that. The alt+ system always feels very janky to me on Windows because on many apps, hitting Alt relayouts the entire app sometimes to show the menu bar on top.